An interactive television (ITV) program provides a viewer with an opportunity to interact with a television show that is currently being viewed. For example, if the show is a game show including contestants, an interactive version of the show may allow viewers to play along with the contestants in the show. In order for a viewer to participate in the ITV program, the viewer must generally be equipped with a television receiver that is capable of receiving ITV programming, and the program must generally be produced with ITV data that is broadcast with the television program.
ITV data is currently encoded into field 1, scan line 21 of a television video, in accordance with a standard set forth by the Electronic Industries Alliance (EIA), the EIA-746-A standard, entitled “Transport of Internet Uniform Resource Locator (URL) Information Using Text-2 Service,” the content of which is incorporated herein by reference. Field 1, scan line 21 is commonly referred to as a vertical blanking interval (VBI).
Also encoded in the VBI line of a television video is closed caption data used to display closed caption text following the dialogue and other audio data present in the television program. The closed caption data is encoded into the VBI line according to a EIA-608 standard entitled “Recommended Practice for Line 21 Data Services,” the content of which is also incorporated herein by reference.
Because both ITV data and closed caption data share a single data channel, namely, the same VBI line, the ITV and closed caption data are transmitted in a time multiplexed format to accommodate both services. If the ITV data and closed caption data are transmitted at exactly the same time in the VBI line, a timing conflict results.
Both the closed caption data service and the ITV data service, however, are generally time critical data services commonly created by separate groups of people. The author of the closed caption service for a television program specifies exactly when a certain caption is to appear on the television screen. The author preferably times the appearance and erasure of the captions based on the program's dialog. Similarly, the creator of the ITV content may time the ITV data based on events that happen in the television program.
In some instances, the ITV data may cause timing conflicts with the closed caption data. In such instances, a lower priority data yields to a higher priority data. Currently, ITV data is deemed to be of lower priority than closed caption data. Thus, although it is desirable to transmit the ITV data at the exact time specified by its author, the ITV data currently yields to closed caption data when a timing conflict occurs. The ITV data may not delay, block, or modify the higher priority closed caption data.
If timing conflicts occur, they are generally not detected until the ITV data is merged with the closed caption data. In most cases, the group creating the ITV content does not have access to the closed caption content when creating the ITV data. Timing conflicts, therefore, cannot be avoided until late in the process of producing the television show after the ITV data has been created. When a timing conflict is detected, the lower priority conflicting ITV data is generally manually shifted to an available time spot to avoid the conflict. The shift in time of the ITV data, however, may be significant, causing noticeable discrepancies between the display of the interactive content and a desired event.
Accordingly, there is a need for a system and method for merging ITV data with closed caption data that causes the merging to occur without disturbing the closed caption data and with minimum timing conflicts. In addition, the system and method should cause the merging to occur in such a way that the timing of the ITV data is maintained as close as possible to the desired event times.